Ionic Liquids as Thermal Fluids for Solar Energy Storage: Computer-Aided Molecular Design and TRNSYS Simulation

Abstract

Due to the great potential of ionic liquid (ILs) for solar energy storage, this work combines computer-aided ionic liquid design (CAILD) and a TRNSYS simulation to identify promising IL candidates as simultaneous thermal storage media and heat transfer fluids. First, a mixed-integer nonlinear programming (MINLP) problem is formulated to search for optimal IL structures, where the thermal storage density integrating the IL density, heat capacity, melting point, and desorption temperature is employed as the objective function and the physical properties, i.e. thermal conductivity and viscosity, are implemented as optimization constraints. After that, TRNSYS simulations of a solar energy power system with the designed ILs as thermal fluids are conducted during a typical meteorological year to further study the practical performance of the IL candidates. Through the analyses of annual system operation performance as well as the long-term cost savings of such a system, the application feasibility and sustainability of the designed ILs for solar energy storage are well interpreted.

Preparation and Application of Paraffin/Expanded Graphite-Based Phase Change Material Floor for Solar-Heat Pump Combined Radiant Heating Systems

“…TRNSYS simulation, one system dynamic simulation method, was first proposed in 2000 by the solar energy laboratory of the University of Wisconsin, which was recently proved to be a powerful tool to ascertain the operation behaviors and the long-term cost savings of the energy power system during a typical meteorological year. − In this work, the TRNSYS simulation was carried out by Simulation Studio software (TRNSYS 16_1) to act as an important validation to further evaluate the running stability and saving-cost of the PCM floor by taking the proposed solar-air source heat pump-PCM floor heating system in Guangzhou (latitude 23.1° N, longitude 113.2° E) as a practical application case.…”

Energy Applications of Ionic Liquids: Recent Developments and Future Prospects

“…A hydroxyl functionalized imidazoliumbased IL, [3-hydroxy-imidazolium][BF 4 ], was found to be the optimal HTF candidate showing the highest thermal energy storage capacity along with appropriate melting point and decomposition temperature. Similarly, Wang et al 383 used the CAMD approach to identify promising IL candidates as HTFs for solar energy storage. An optimization problem is formulated with the thermal storage density as the objective function and thermal conductivity and viscosity as physical constraints.…”

Computer-Aided Molecular Design of Ionic Liquids as Advanced Process Media: A Review from Fundamentals to Applications

“…Wang et al 27 combined MINLP-based IL molecular design and TRNSYS simulation for the identification of promising IL candidates as thermal storage media and heat transfer fluids for solar energy storage. The MINLP problem employed the objective function of thermal storage density that integrates the density, heat capacity, melting point, and decomposition temperature, while considering the constraints on physical properties namely thermal conductivity and viscosity.…”

“…One type of extensively studied application of ILs is to replace traditional organic solvents in different separation processes including gas absorption, − extractive desulfurization and denitrogenation of fuel oils, , extraction of bioactive compounds, , extraction of metal ions, − removal of contaminants from wastewater, − etc . Another type is to employ ILs in different organic transformations as reaction media and/or as catalysts to modify catalytic activity and recyclability, for example, substitutions, additions, acid-catalyzed reactions, base-catalyzed reactions, and transition-metal-catalyzed reactions. ,− A third type is to utilize ILs for energy storage and conversion materials and devices, such as phase change materials, − electrolyte and electrode materials for batteries, and supercapacitors. − It is hardly possible to present a full list of potential applications of ILs, and the ones mentioned here are only some typical examples. However, despite the great interests that ILs have sparked, the choice of IL as the key decision in designing a specific IL-based process still heavily relies on the experimental test of a small number of candidates in most cases.…”